I was a vegetarian restaurant over the weekend and ordered a meal that had "tofu" and "soy protein".  The soy protein looked somewhat like steak, but was whiter and tasted similar to steak.  I asked the woman what it was, but she could only tell me that it was "soy protein".  I am looking to incorporate this ingredient in my meals, but I am not sure what to get or where to get it as I understand there are many types of soy protein.  I know that I haven't provided a great description, but does anyone have any educated guess about what type of soy protein this could be?  Also, where is a good play to purchase soy protein?  Thank you. 
This sounds like seitan to me, or mock duck, mock chicken, braised gluten, or one of the various other names for it.  It is made from wheat gluten and has a texture, as you state, between tofu and a kind of rubbery steak.  For vegetarians, it is my opinion that it is the closest of the simple meat substitutes to a sensible "meat" texture.  I find it easiest to buy the fried variety canned in the UK from Chinese food shops and some large supermarkets.  How the seitan is braised/prepared makes a difference to the final texture and flavour hence getting the different mock varieties.    Companion Seitan "Tidbits" (Cha'i-Pow-Yü) I find are very useful for curries and that sort of thing.    It should be quite easy to obtain in your area.  There are a lot of modern western meat alternatives that are very accurate and are a combination of soy-based TVP and seitan.  I know Tofurky is popular state-side, a company called Redwoods covers similar bases in the UK.     