Mu current thought is :
Deep fat fryer (preferably, like the cheap Aldi ones I got, with a heating element outside the pan, so nowhere for fluid to hide or overheat.)
Basket arrangement to hold the PCB at a useful height
Pyramidal aluminium hat, quite tall. This has:
riveted-on L-section extrusion, running vertically, to act as a heatsink. As many sections as will fit.
A vigorous PC fan at the top, blowing air down all 4 sides of the pyramid, and over all these heatsink strakes.
A USB camera, an illumination LED and a (say) 16x4 PIR widget (The Melexis one goes hot enough) all at the top. It shouldn't get hot up there.
The hat needs to drip the fluid back into the fryer, and avoid it escaping, since it's expensive, and gets absolutely everywhere! (Lesson learned from simply using the fryer unhacked).
Making it all rectangular should make fabrication easy, but round would also do - I'm wondering whether I should get one of those
http://search.ebay.co.uk/171229554056 - easy enough to wrap cooling coils round the top section, and heating it with an induction hob should avoid messing around with strapping resistors together.
What I'd really like is some heatproof material that floats on galden vapour, so I could easily measure (and control) the vapour level. Hints would be very welcome!
Another thought I have from time to time - vapour phase is all very spiffy, but for prototype purposes, where you don't need to do boards back to back very often - can you just dunk boards in a bucket of the stuff, and heat it up? Or do the components float off in a comedy manner?