The only thing like the Hagstrom pickups are other Hagstrom pickups. Anything recent (like Chi-Sonics) are optimized for the modern player. If you can find a vintage set grab them - they do not come around very often at all. The tone on those is quite amazing considering they look like crappy little pickups.
The original Bi-Sonics are nothing like these other than being single coils too. If you want to do some more routing you can get new versions. Fred Hammon has long since gone out of business, but several other makers offer them. They look like this.
I will vouch for them - they really do sound great! I have a early 60's Coronado IV with the original Bi-Sonics and it sounds awesome.
Yam BB Club #3; Lane Poor Club #5;
Haggy Bass Club #7; Warmoth Club #18;
Tele Bass Club #24; MM Sterling Club #25;
B.C. Rich Club #52; U.S Peavey Club #306; Sunn Ownwers Club #82