Are the calculations vanitygen has to perform of the same kind as bitcoin mining? Could somehow a hardware miner be used to accelerate those calculations?
They are, for the most part, very different.
Miners (partially) calculate a double SHA-256 hash of some input.
Vanitygen is based around a bunch of much slower
elliptic curve based math (plus also requiring an SHA-256 calculation, which takes relative little time).
Mining ASICs would unfortunately not be useful.
Maybe some FPGA miner can help us accelerate the calculation.