How about a 20L tea urn as a boiler and a cheap and cheerfull 25L esky for mashing. You can use any old pots to take your sparge water to temp on the cook top.
Fixing a tap into the esky can be a pain in the arse. Difficult getting a seal sometimes, but neoprene washers seem the go.
I made a simple rectangular copper manifold from a tee piece and 4 right angle bends (think it was 1/2" dia). Tapped the end of the straight pieces to slightly distort them so that they are a push fit into the fittings. Makes it easy to take apart to clean. Clamped a piece of poly tube onto the inlet of the tee piece and this slips neatly into the inside of the tap connection.
I'm with Jovial M on holes v slots. Just use a hole punch to dent the copper a little and drill lotsa small holes.
I use an old sleeping back to cover the esky and keep the temp constant. Twenty litres maybe drops 1 - 1/2 degrees over an hour and a half.
Haven't got a sparge arm yet, but someone came up with a good idea somewhere. Fold some aluminium foil over to double thickness and shape it to the inside of the esky. Just rest it on the grain bed and poke a dozen or so holes in it. Then, when you add your sparge water, it doesn't disturb the filter bed.
Oh, and a length of poly tubing that will fit over the tap outlet and drop down to the bottom of your boiler. That way you don't splash it as it drops in.
I bought all the bits 'n' bobs one Saturday morning and did the first brew that evening. It'll do until I get my 3 keg setup off the ground.
ps If you're in the Sydney area I may be able to wangle a tea urn...
