So...
There IS a portable version of LMMS on this site, but the current version is 0.4.4, and as of 3/12/12, the latest version is 0.4.13. If you guys could update it, I would be very greatful. 
Thanks!
LMMS Portable LATEST VERSION 
New: HandBrake (Feb 20, 2026), Platform 30.2 (Feb 17, 2026)
1,400+ portable packages, 1.2 billion downloads
Please donate if you can!
Not sure you'll get anywhere, but try posting an update request in that thread as well.