Went through the Tunisian / Libyan border at Ras Jdayr in March 2007 with about 10 other bikes. Can't predict what can happen. Leaving Tunisia only took about 1 hour. But at the Libyan part we arrived at the same time as a convoy of French 4x4's so total process took about 7 hours. Not only that it is also the main trade route across the north between Tunisia and Egypt so there were big convoys of trucks also taking up the customs and border officials time. Once stuck at the Libyan entry there is no food or drink available. You can change money and the toilets are semi respectable ! Immediately after are some OK food places.
Like all borders get there early, be prepared for a long wait. If you are aiming to get to Tripoli after crossing, the road is OK but very busy, lots of congested towns, strong cross winds from the sea and some of the worst driving standards you will ever come across. If it is getting dark they don't use lights ! Had a great time though and the country is well worth exploring (with your appointed guide of course).
We had permission to get out from a border further south but it was closed to foreigners whilst we were there so had to detour back to Ras Jdayr.