Radio Shack RSU still carries the bulbs/LED. I ordered a few a couple months back. All you have to do is slide the old one out, slip the new one in the slot, and resolder the two wires. Takes only a few minutes to do. IIRC, they run about $3.50-$5.00 each (?).
Tell the manager to look up the part under RSU parts. I can't remember the number off hand.
2-Pro 668, 2-Pro-651, 1-Pro-652, 2-Pro197, 3-PSR500, 2-BC4-6 TS, 6-BC100, 2-BC100XL, 2-Pro-2050, BC70, 2-Pro-96, 3-Pro-2096, 3-BC210, Pro-90, 4-BC200XLT, BCIII, 2-BCIV, Other toys; Mercedes .