You could possibly find a welder that welds fuel tanks. You can also use tank lining chemicals. Kreem does work but it does not seem to last. I have used red kote and seems to be working well. Next time I need to line a tank I am going to try POR-15, I have used POR brand on car frames and am impressed with that product so I will give the tank liner a try.
I believe you will have to find the same model tank
Casswel sealent is the best stuff out there IMHO its a 2 part epxoy that will hold up to ethenol. They recomend it for pinhole leaks. Kream is the absolute worst sealent, it WILL breakdown in ethenol and clog your carbs (words of experience). POr 15 is a good product but can't say how it will preform on pinhole leaks.
Next time I need to line a tank I am going to try POR-15, I have used POR brand on car frames and am impressed with that product so I will give the tank liner a try.