I am on Starburst ROM 4g Epic touch. There is no stay awake option in development, which left me searching for the solution. I've installed 2 apps (free) that solve it for me.
First is "stay awake" (duh!) looks like it's been removed and added to the market. Option to not turn off when plugged in, or never turn off (also removed from settings).
The other is "keepscreen", which will not timeout the screen for the apps you select. So now you can have a super short timeout system wide, but override it for those apps where its annoying. Ideally there would be a custom timeout option for each app, but keepscreen as it is, is a keeper!