Ok so you need a stable voltage without an overly thick wire. You also don't want to put bulky components near the load.
So what are our options.
I wouldn't nessacerally rule out a regulator chip near the load. There are some impressively tiny switched mode converters available nowadays though heatsinking can be an issue.
Another option is "remote sensing". A pair of thin wires is brough back from the load to the power supply. This lets the power supply measure the voltage at the load and compensate.
If we know the resitance of the wires we can just build a power supply that compensates based on he known cable resistance but that risks overvolting the load if the cable is shortened.
Linear techonlogy has a clever soloution to this which they call virtual remote sensing. They use the decoupling capacitors in the load to measure the cable resistance and compensate for it without the need for physical sense wires or known cable lengths. The downside seems to be that it's measurements will cause some output voltage ripple.