How can I get my bra straps to stop slipping?
Calvin Klein’s 356 adjustible strap bras sound like what you want, but I believe they’ve been discontinued (which I’m not very happy about). You might want to try and find them online, though – I’d post a link, but I’m writing this on my phone. The straps can connect to the back either in the usual place, or ~2 inches in. I like to wear them the latter way so that my bra straps don’t show when I wear tanks, and it might also solve your problem.