I did a relocation myself with a $25.00 plastic reservoir from US Plastics. Got some steel wire from Home Depot and utilized the existing holes on the body to mount the reservoir. Less capacity than the OEM reservoir but it has worked for me even for week long road trips. Mine has never leaked and it's gone up pretty high in elevation at 9k+ with no issue. You'll need to drill two holes and use weatherproof silicone to seal the pumps.
1.5 Quart Natural Multi Purpose Tank with Mounting Tabs - 7.74" L x 3.62" W x 5.9" Hgt. (2.25" Neck) | U.S. Plastic Corp. and you need the appropriate cap too.
I'll post some photos later.