Here are a selection of JBE turntables and parts that have sold recently. Without stating the obvious, those which include an arm, are worth more than those without, seemingly to the tune of perhaps £100 (with a typical base SME arm in place).
JBE Series 3 - Sold via eBay 13/4/12. Price £125. Summary: Seemingly clean example, no arm.
JBE Series 3 - Sold via eBay 28/4/12. Price £210. Summary: With SME arm, with cracks to dust cover.
JBE Series 3 - Sold via eBay 29/4/12. Price £217. Summary: No arm and with one-off control box.
JBE Micro absorber feet - Sold via eBay 26/4/12. Price £40. Summary: one of three lots that also included a platter and a control box. No prices on the latter items.
JBE 3001 - Sold via eBay 6/5/12. Price £122. Summary: First clear acrylic plinth I've seen after my own 3001. Very rare. Needed some TLC and lacking an arm.