I think that you may have to take a longer more considered approach in choosing the right conversion to suit your needs.
I'm toying with the idea of producing a fact sheet in the guise of a xl spreadsheet:
Basic image of conversion type; advantages, disadvantages, approx cost etc etc
Problem is that it is totally horses for courses. What is good for one is totally inappropriate for another.
We discovered that having the bongo unconverted for our tour last year in France made us rethink how we actually 'campaign' on the road:
a. What we take & out of that do/did we actually need or use it!
b. What you take - does it have more than one use (bongos don't have acres of space)
c. Current & future needs; i.e. kids or grandkids insisting on coming along with you!
d. Ease of use - the conversion has got to be user friendly - no point in spending your hard earn dosh on something that has poor storage or restricts seating/cooking etc........never fry inside t'bongo....oh no!!
Just to put it into context. We knew that a side conversion is what we wanted, as we plan to wild camp in Scotland and want to have a small foot print - no awning etc etc! However, a rock and roll bed (which we had previously) was totally unsuited to our needs as a family. It's fixed, has little storage and limits where additional storage cupboards can be placed in the cab because it is fixed! So, after reasearch and a gent called Rupert at Free Spirit Auto who was very patient and took lots of time with us, we had enough to form an opinion on which seating arrangement would be best for us!
So, after a little more shopping around and actually seeing a similar conversion to the one we wanted - we chose 321 Away to do the deed and we haven't looked back since!
If at all possible, find a very generous owner who would let you use their bongo for a weekend with a fit you'd like or find a rental outfit. Also at the big meet - spend ages just looking round and round and round until you have sponged all the info you need and then pounce!