The max length sold at the parts store are 6 ft, the run from front ABS pump to rear wheels is close to 14 ft.
You can buy 2 long lines with metric bubble fittings (tell the guy at the shop you need european fittings line with metric nuts) - these new fittings are to be used on the pump and slave side.
for joining the two lines buy a union and a couple of double flare nuts (same autoparts shop would have them for cheap (less than a 5)
rent a flaring tool from the parts store along with cutter and cut the line to size, install the double flare nuts and flare the end. then install on the car. look at youtube to get ideas of how to bend the line without tools
For easy flaring use a dab of silglyde grease.
Some NAPA shops with actual repair/machine shops attached to them (or a decent indy mechanic shop) will make you a flare for a dollar or so each or in exchange for donuts too
. If you can find such a shop then just measure the length required and buy the line from that NAPA along with the line nuts and have them flare it. Then all you need to do is bend the line to shape and install it.
tip:
buy a line wrench or a plumbers pipe wrench or some really good and sharp locking pliers because those line nuts would be frozen to the fitting pretty good.
I would suggest you very closely inspect all the lines, use a wire brush and blade scraper tool to inspect as if you have one rusted line, the chances are that the rest are in the same shape. (my first brake line job on a car was an avalanche of failure - I would repair one and the next would pop - I learnt that the hard way to repair brake lines all in one job.)