can a six string bas be tuned to (F# B E A D G) do you have a bass like this or do they even make strings like that????
A six string can be tuned like that. Probably if you can't find a set tuned like that, you could get a five string set and then find a single string for the low F#.
The biggest problem with this tuning is not finding an F# string but finding speakers that are able to handle such low frequencies without sounding like mud. Notes that low also take a ton of power to create.
You might also find problem with the nut and bridge. So you are going to have thicker strings than these were designed for in each case - so you can file the nut - but it may be the case, with a thick B next to an even-thicker F# - you will run out of room and one slot will go into the next or make it so thin on the top side that the nut breaks. Similarly with the bridge - if it is the type where the string goes through a hole - you can file it - but you will be weakening the structure and it might end up breaking - you wouldn't be able to get an F# through the body as well, unless the bass had been designed with this in mind.