I can't really say that I know of a pickup that sounds similar to the Seth Lover that is considerably higher output and tighter bottom.
The Seth Lover has such a distinctive tone and so much of it is due to that looser low end and such.
I have opted to use the Pearly Gates set instead of the Lovers when wanting to play with more gain and volume, as they give me a great vintage PAF kind of sound but with less noise and squealing, and while it does have a spongier bottom end it's a bit easier to tighten it up than with the Lovers, at least in my experience.
I think other pickups such as the SD 78 and even the SH11 Custom Custom are good alternatives too, definitely tighter and higher output/lower noise and they're excellent pickups, not sure I'd say they're overall very "similar" to the Seth Lovers though, but I guess that's subjective.
I agree with the comment earlier about contacting Duncan's custom shop/customer help, they can give you several suggestions for both custom shop options as well as what current production models might suit your needs best. They also can customize your Seth Lovers such as wax-potting them in order to make them more easily useable for higher gain tones.
I'd seriously consider getting in touch with Duncan and seeing what they could suggest for you. I'd be interested in hearing what comes of it if you do.