I'm guessing that your site will be broken on small devices because of the absolute positioning on the wrapper and the silly centring routine you have used. On smaller screens the layout will have slid off the the left and be unreachable.
Change your wrapper to position:relative, remove co-ordinates and then use margin:auto to center it and then it will at least stay in the viewport
Um, you totally want to check out the research of PPK (http://www.quirksmode.org/blog/archives/2009/03/testing_mobile.html) because he's probably tested the most phones and mobile browsers out there than anyone else. And, there are some proprietary browsers who insist on rendering things like crap, and there's little you can do. But I think keeping tabs and reading the results from PPK's research will give you a better idea (he might also link to emulators but not sure... and besides, Vodafone gave him like 60 phones to play with... the guy walks around with at least 6 phones with him at all times).