Most good auto muffler shops will build one.
But, they mostly use benders that reduce the inside diameter of the pipe during the bending process. This is likely OK on cars but not so nice on motorcycles.
If you look through exhaust tubing web sites you can find mandrel bent tubing in many different configurations. 2 90 deg bends should give you all the angles that you need.
Then just cut the bends at the angles you require to connect the pipes.
FWIW, I started with a link pipe from a GPR silencer. This pipe was OK but was difficult for me to adapt to the Spark Arrestor that I require in the USA for off-road riding. The link pipe provided was very very close and I only had to modify the silencer end to get it to mate to the Suzuki can. Dunno if the GPR link pipes can be had seperately.
The OD of the Suzuki head pipe is about 43 mm while the pipe exiting the square flange on the GSXR is 58 mm so some reduction has to be engineered in along the way. If you can find a pipe with the 1000 link pipe attached, this will help you start the fabrication process. The link pipe will have the square flange and pipe alreay attached and the gasket between the silencer (yes, there IS a muffler gasket) and the link pipe present. Then you can just cut the link pipe at whatever point you went to continue your build
Be sure you get the "(x)40f0(x)" (stamped in the aluminium outer shell) pipe from the 2000-01 GSXR 1000. The 35F0 silencer from the 750/600 is also the same outside size but has just slightly smaller internal pipe size. It isn't Titanium but the weight difference it slight. This one may be more redily available.
The use of these pipes for DR650s is likely not quite so popular in your part of the world so it's usually quite probable to find one at a breakers.
If you haven't seen this site yet: https://docs.google.com/presentation...nt#slide=id.i0
Take a look since it has good information. The link pipes for the DR650 are close but the end nearer the engine has a large "UP" angle that is not used on the DR750. It may be a starting point but would be a shame to spend all that money and then cut the pipe up.
Oddly enough, this silencer has no detectable (to my butt dyno without any gas analysis) effect on the bikes standard jetting so there's not much mucking about there.