There are several threads already on here of this nature, Bob. Try these....
http://basschat.co.uk/topic/67545-no-pain-no-gain/
http://basschat.co.uk/topic/9103-double-bass-buying-guide/
http://basschat.co.uk/topic/171751-how-to-buy-a-double-bass/
THere are 55 pages of threads on Electric uprights and double basses here and most of what you will want to know will have been discussed in there. ALso, if you let us know where you are, someone will probably arrange a meeting with you so you can try a bass out etc.
Nice to have another jazzer one here!