i don't have the time limit problem. i recorded a 30 min conference into MSPD and i have tried recording abt 8-10 mins into the phone memory. it really depends on how much memory you have left in your phone or MSPD.
the only difference i encounter is between a normal and high speed MSPD. the video is very smooth on the high speed card
Sounds like more than a firmware issue then as I too had no problems recording a 10 minute video as a test today. I thought there might be a problem with the speed of writing to your memory card and some form of caching may have been taking place but that doesn't seem the case.
Have you tried reflashing your phone with the current firmware? Otherwise it sounds like a return to supplier.