Sorry but you dont need all american or high draft pick prospects on your Oline to have a great unit.
Following that logic out to its conclusion - We should deliberately wait until after the draft and find the worst remaining linemen available.
There may be great units that don't have high-profile linemen on them. But having a Jonathon Ogden on one doesn't hurt. Having a Boselli as your LT doesn't hurt. Having Larry Allen (in his prime) on one doesn't hurt. Having Leonard Davis on one doesn't hurt.
Within the context of total team priorities, you do whatever it takes to put the best five players out there - whether they're comprised of UDFA's and/or high draft choices. Whatever options are available to you - a high draft pick, a sleeper, a FA, an UDFA or via a trade - you take advantage of all possibilities to get the job done.