Chiguireitor(UMO dev) did do some work on a webgl miner some time back and tbh that would be best place to start but I dont think he released the source (probably due to beta/alpha code) might be an idea to drop him a line here or via his twitter @johnvillarz and see if he can help point you in right direction before you go too deep
on side note next year might start to see asic's for blake256r8 so not sure too much work on GPU/FPGA is best time spent unless its for learning or fun
I will address the second point first. I have heard rumors but I haven't seen anything that is solid yet. If you have better information then please share it if you can. I was under the impression that the blake256r8 ecosystem was not capitalized enough to justify the tapeout costs of an ASIC. I have been mining on eu3 and I never see more then 20 miners at a time. If an ASIC is made then I will be very disappointed since I really don't want/can't get involved in a arms race. Until the dark day arrives, then I am trying to spend up GPU and FPGA
Your first point is useful to me and thanks. WebGL is a JavaScript binding and probably not what I am looking for but it is interesting nonetheless. This is the post that I was referring to. http://bitcointalk.org/index.php?topic=4618.40