You might try a retail place like Fastenal (there are stores in Plano, McKinney, and all over DFW). Sometimes Elliot's Hardware in Plano can be a great metric source.
But metric studs?... wow, I usually have to order any studs we use (for motor mounts and some other products we manufacture).
McMaster Carr is super "easy" to order online from, but Metric & MultiStandard's prices (Irving) are always lower (no online ordering). Ditto Fastenal... their online ordering system stinks, and the pricing is terrible online compared to having a commercial account in their store. So I'd look at MMC online first, then call MMS.
Just getting the right stud length is tougher than it might seem. There are several DIN standards that are used to measure "unequal length studs", and it takes looking in books and pictures to figure it all out. There's usually an overall length (OAL) and a length of threaded stud on one side of the center shouldered portion. See what I mean below... That is an M10x80 stud, and in this DIN variation it has the same amount of threaded portion on both sides of a set width center section. It gets way more complicated when the two sides are different threaded lengths.
We stock all manner of M8-1.25 bolts that we use on camber plates. Plated, bare black, 25, 30mm long, and some more. If you're near Allen/McKinney give us a ring and I'll toss you a handful of these to try, if it gets you out of a bind. I literally have thousands of these things in stock.
Good luck,