Randy Mosher described a beer in Radical Brewing that was "wasteful of malt"... Double Ale... Mash in a normal beer... instead of running the wort to the boil kettle, it is reheated to strike temp again then added to another set of grains and mashed again... (if you have the room, could prolly do a parti-gyle of this and get 2 batches... one strong, one small)...
His 5 gallon recipe is:
20 lbs Maris Otter pale
2 lbs Biscuit/amber
4 oz EKG (5% AA) @ 90 min
3 oz EKG (5% AA) @ 30 min
2 oz EKG (5% AA) @ end of boil
2 oz EKG (5% AA) Dry Hop
this should give OG 1.120 (29 P)
and take about 8 months to mature...
directions are: Split grain in 1/2... mash with 1.5 qt/lb @152F for one hour... vourlaf and run off... sparge to collect 4 gallons... heat to strike temp again... clean and refill tun while heating wort... repeat mash and sparge to collect 6 gallons of wort... then do your 90 minute boil...
as he says "The English would typically "cap" the mash with more (2 pounds, or 0.90 kilograms) biscuit malt and run off a normal session ale, and you can do this if you like."
Anyway, all that said... perhaps with a little math etc, you might be able to adapt that to your brew of choice...
stupid question... would 5 gallons of 1.120 be equal to 10 gallons of 1.060 if you dilute it out???
hmmm.... ProMash says that at 75% efficiency, for 5 gallons you should get 1.125 for the 22 lbs of grain and for 10 gallons you should get 1.062, so I guess that's about right then
(oh, and the 35 lbs should get you about 1.092 ish at 10 gallons w/ 75% efficiency)
math makes my head hurt!!!
Hope that helps some...