Making higher power resistors from arrays of lower powered resistors is a trick that I was shown many years ago, and it works well in some cases.
What brought this to mind is that I got my regular email ad from Marlin P. Jones' surplus place, and they have 1 ohm, 10W resistors on sale for $0.19 each. Eight of these in series makes an 8-ohm, 80 watt dummy load for $1.52. Not too shabby. Get 16 for $3.04 and you can make a 16 ohm, 160W resistor by putting two 8-ohm strings in series, or a 4 ohm 160W resistor by putting the same 8-ohm strings in parallel. Go really crazy and buy 32 of them for $6.08 and you can make up series/parallel combinations to get 2 ohms, 4 ohms, 8 ohms, and 16 ohms at well over 100W.
That's nice, but how to mount them so they're usable? One easy way is to make a breadboard - the old fashioned kind, made with a real piece of wooden board (or plywood, for stability) and screw in short screws in an array on the board, then soldering the resistors to the screws, which hold them up off the burnable wood and ensure lots of air circulation to let the resistors get HOT without damaging anything. Add a terminal block at one end for input/output and perhaps even patching for different load ratings, and you get a very flexible bench accessory.
For extra points
If you want better modelling, most 8 ohm speakers are actually about 6 ohms resistive and 6mh more or less due to the voice coil inductance. You can buy 6.8mH/4A inductors at Mouser for about $6.50 each. Use one inductor and six 1 ohm / 10W resistors for each "8-ohm" dummy resistor and you get much closer to a real speaker - if this is what you want to do.
