Is BAMT 0.5 only for GPU rigs?
yes
Doesnµt the included cgminer support fpga devices?
Some but not all. It's an older version of cgminer, 2.3.1 I believe, not 100% sure. So anything supported in that is good to go out of the box. You can build an newer version of cgminer on BAMT if you have enough Linux knowledge. Or, you can bug lodcrappo to update the version and push it out on the fixer, good luck on that.

Hints on upgrading to current version of cgminer here:
https://bitcointalk.org/index.php?topic=65915.msg873655#msg873655https://bitcointalk.org/index.php?topic=65915.msg972078#msg972078Take your pick, I used the first link and just had to update the sources to reflect current versions. It's been running about a month now without issue for me anyway. Here are some hints for the cgminer options to add in the BFL's:
https://bitcointalk.org/index.php?topic=28402.msg989549#msg989549If this works for you, please remember to donate to lodcrappo to keep supporting BAMT.