I would assume so. Steam isn't as strict as Apple is with regards to editing the app. Just make sure you don't verify game files; it'll probably revert any changes you've done.
Notes about having a Steam Avadon Forum: someon would have to maintain it, and I doubt Jeff would want to: he probably would be more interested in developing games than moderating forums.
Considering that I own the first three Avernum games and I haven't played through all of them. I was going to go back to play Avernum 1, but I got lost without a quest book.
One question I have is price: how much is it going to cost, especially for those of us with a license of Avernum 1? I mainly ask this because I have no money
I myself would like to congratulate Jeff for Avadon being in the Staff Picks as well as in "The Best Games You've Never Played" section of the Mac App Store.
So any news on the Steam version, or is it going to be delayed until the Windows version gets developed?
As for the price difference: you are only getting the Mac version. Some people like to have matching versions of their games for Mac and Windows. Mac App Store apps, by agreement, must not have their own copy protection in them. This means that you can install Avadon on as many Macs as allowed by the MAS EULA.
Avernum 1, 2, and 3 are PowerPC CFM Carbon, so you need Rosetta installed in order to play them.
Unfortunately, this will be an issue in Lion, which is dropping Rosetta support entirely.
Yes, another one of these from me. Basically, is there any plans for the Avernum Trilogy (And SpiderWeb games in general) will be made available for the Mac App Store?
I'm mainly just curious.