Not too much traffic on this one I guess. So what's a boy to do? His own damn searching, that all!
So for you Lakland owners who prefer to string through the body and like your tapered B string, here is the list I have come up with that does indeed have what you are looking for.
I am only going to list the manufactures, listing all the different model sets from nickel to stainless steel would be too time consuming. One of my main sources was juststrings.com plus a bit of googling and checking out the string manufactures web site. If you are looking for a specific set I suggest searching juststring.com, most manufactures web sites have very little information on them.
The following manufactures
do make a set in an "extra long scale" (37") to accommodate the string trough option and
do have a tapered B string.
Fodera
Ken Smith (thanks NJL)
La Bella
S.I.T. (tapered E & B)
Other manufactures that were mentioned that do, but I could not confirm is:
D'adderio (ex long scale, yes. tapered B??)
Warwick
Pedulla (probably not, their basses are 34" and do not string through the body)
DR does make an all tapered set (Long Necks, S.S. only), and most of their string sets will be long enough to string through the body, but I can not tell you if they make a set with just a tapered B.
MTD does make some sets with only a tapered B, they do make a 35" scale bass, but their strings may not be long enough to string through the body.
Any Lakland users out there that would like to contribute please do. I don't think that this is worthy of a sticky, but will be good for those that do search the forums. If I find out more I will edit this post.