The G8 Game Timer sounds like what you're looking for, and Greg Aleknevicus has has a very nice review of it in The Games Journal .
It seems like it might be hard to come by these days, as its out of stock in many stores, though it appears the manufacturer still sells them directly .
From the review: To my mind the device only really works well when playing games in which the players take sequential, non-interactive turns of several minutes duration.
While this might seem rather restrictive there are lots of games that do fall into this category.
Also, it's precisely these games in which a timer is most useful.
The aforementioned Tikal is one such example and Vinci is another with which it worked quite well.
Ultimately, I can't really say whether I recommend this or not.
Not because I don't think it's a worthy piece of game equipment, it is.
Rather, because its usefulness will depend so much on the particular game and group that's using it.
As mentioned in the review, a timer is less useful in certain games.
Games that involve lots of interaction with other players during your turn, such as trading in Settlers of Catan, mean that the length of your turn doesn't depend only on how fast you play, but also on how fast your opponents make decisions.
I don't think that Settlers of Catan would work well with a timer.
You also need to consider what you do when a player runs out of time; do you simply eliminate them from the game?
In a two player game, when you run out of time you lose, and the other player wins; in some multiplayer games, elimination can disproportionately benefit one player over the other ones.
Then there are games in which people's turns generally go fast enough that the timer is more of a distraction than a benefit.
I would put Carcassonne in this category; it doesn't usually take long for someone to place a single tile.
If people are taking too long, there's a simple house rule that I use: people draw their tile at the end of their previous turn, instead of the start of the next one.
That way, they have everyone else's turn to think about where they want to place it, and the board only changes a bit by the time it gets back around to them.
That said, there are some games in which the timer would be useful.
Games in which elimination doesn't disrupt the game, which have long turns in which each player plays independently of the others, and which are prone to analysis paralysis.
boardgames.stackexchange.com/users/112/Brian Campbell
I thought it was worth adding an update to this that I ended up using a free Android app for this:
https://play.google.com/store/apps/details?id=de.schwider.multiplayertimer It works very well, and is able to switch to time whoever the phone is pointed at by using the phone's compass.
It also calls out the name of whoever's turn it is.
boardgames.stackexchange.com/users/122/tttppp
I had the same problem
so I created a free iPhone/iPod touch app for this-- it supports up to 6 players and is very simple to use.
Check out "Game MultiTimer Free" on the app store.
As someone said above, it's not a great model for something like Settlers, but it works great for games like Rummikub or scrabble.
boardgames.stackexchange.com/users/None/
I don't know if they exist, but it is fairly easy to create using kitchen clocks or stopwatches.
One for each player.
Or it can be programmed on the computer.
boardgames.stackexchange.com/users/45/Toon Krijthe
I an game like Settlers of Catan, a timer like that wont really work.
What should happen when a player uses too much time?
Should he be excluded from the game?
Using cumulative timing in multi player games usually wont work well.
Also for Settlers of Catan, there is a lot of player interaction going on, trading haggling etc, which is a big part of the game.
This holds true for most of such types of games.
I found it much more useful to either: Use a single timer, fx you can only use a certain amount of time each turn.
If things are deadlocked, fx can't make a trade in Settlers that both parties can agree upon, give a count of 5 to make a move, or pass the turn.
boardgames.stackexchange.com/users/None/
When playing for fun with friends I wouldn't use a timer to limit someone, after all not everyone has the same favorite game and spend different amount of times on it so they'll know the combinations faster/slower.
It just feels (for me) wrong and more competitive then a social fun thing which is why I play them at all.
So I'd vote for not using them.
Anyway if you disagree then there's always those small sand timers that even comes with some games (drawing games I think?)
you can pick up a few of those for multiplayer where each has his own I suppose.
1 min sand timer on Amazon is like $1-2 a piece.
boardgames.stackexchange.com/users/93/Don
I'm interested to know if there exists something like a chess timer, but for an arbitrary number of players.  I would like to use this for games such as Carcassonne and Settlers of Catan, where each player's turn is largely independent of the other player's involvement.  Assuming there is a product like this I would like to hear whether you have found it helpful to play with, or whether you think it causes more problems than it solves.
Multiplayer timer for board games
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boardgames.stackexchange.com/questions/490
boardgames.stackexchange.com/users/122/tttppp
Try the G8 Game Timer or the Game MultiTimer Free. You could also create something like this using a stopwatch or a sandtimer. The  G8 Game Timer  sounds like what you're looking for or "Game MultiTimer Free" on the app store.  Alternatively, you can use a kitchen clock or stopwatch for this purpose or one of those samll sand timers that come with some games.
The  G8 Game Timer  sounds like what you're looking for. Check out "Game MultiTimer Free" on the app store.   You can use a kitchen clock or stopwatch for this. There are always those small sand timers that come with some games.