This has already been done in Finland (Score 1)

YLE, the finnish equivalent of BBC did a radio version of all HHGTTG books in the 80's (25 x 30-40 minutes). I didn't actually know that BBC series wasn't as long, because I thought that YLE version vas just translated version of it. (Only weird thing was that I couldn't find BBC episodes 13-25 from any P2P network..)

I've heard both BBC and YLE versions, and I think YLE has better actors. Especially the voices for the Book and Marvin are better than their english counterparts. Too bad that most of you can't understand finnish..