I've noticed similar behaviour but I don't have any actual proof that it is Transmission. Every so often when downloading big torrents I find that my MBWE (mine is a bluering 1.5TB) just hangs. Can't ping, can't ssh etc. Since I'm using a ramdisk I can't see any logs either after reboot.
In the past I'd worked around it by limiting the number of connections Transmission will accept, limiting the download speeds, how many torrents are active at one time etc. But lately with a 10Gig torrent it just wouldn't play nice.
Recently I tried an experiment of creating a swap file on the disk of 256MB giving the MBWE more swap to play with. (The new 256 + existing 100 or so). Everything seems to be working fine now although I need to leave it running for longer to get a better idea if this has solved the problem. (My suspition is the box runs out of RAM, then swap also which basically means everything just hangs) You have to remember that the MBWE only has 32MB of RAM and an arm926 core processor - even the iPhone has a faster cpu! Transmission is pretty light on resource requirements, but even so 32MB isn't much to run an entire OS, serve files, and handle massive torrents all at the same time.