Interesting thread going on at FSB about JFET circuit designs. Soulsonic posted a biasing setup that looks really interesting - the point being you can set the DC bias with minimal effect on the AC.
Here's a link to the thread (http://freestompboxes.org/viewtopic.php?f=28&t=26077&start=40)
(http://freestompboxes.org/download/file.php?id=26343&t=1)
I don't really feel like jumping in a fsb thread, but:
There is nothing you can do to not have JFETs have variable gains.
Positive voltage on a gate will alter the signal level just like baryon the drain or source voltage
Who gives a crap about 'variable drain loads' in most pedals? We're talking about a couple k at most for j201 and a few hundred ohms for 2n5457s. And if it's followed by another stage it's dividing against a 1m resistor, which is an imperceptible amount of division.
I don't see a clear enough advantage to warrant a 66percent increase in resistors and the need for more filtering caps to make the Vb approach how quiet and stable GROUND is.