What you described does sound like a bad wheel bearing. Once it's in the shop, the mechanic should immediately see a bad bearing when the wheel is taken apart. The grease seal should be replaced with this job.
If the bearing doesn't show any obvious damage, you'll have to search elsewhere for the cause of the "roar", but I think a new wheel bearing will cure the problem.
Please post back with what the mechanic finds.
95 E320 Cabriolet, 131K