I have a set of cheapo highway pegs on my bike now but I figured I'd do a write up here to cover what I did for the 750 as well as the 1500.
Neither the 750 or the 1500A have a decent place to clamp on highway pegs. There are no straight areas vertically or horizontally on the side to clamp them so they're straight. So here' how I made them work.
I was working at a place that had a machine shop and a supplier where I was able to get scrap. They sent me over a spare piece of 5/8" solid stainless steel square stock (boy, that's heavy!)(don't quote me on the size, it's off the top of my head and also you "might" get pegs that use different dimensions.So measure out what works for you. Use the piece of square stock that joins the pegs to the clamps for size). I measured out and marked where I'd need holes drilled (total of four, two for the pegs themselves drilled just like the small bar that came with them and two towards the center that will be used to mount the bar to the engine guard. The holes towards the center on mine were not equal-distant from the ends because the engine guard rails are not equal-distant).
I used the clamps that came with the pegs to mount the square stock to the engine guard. I think I had 3/8" (maybe 1/4") holes drilled for the center holes (the end ones are determined by the mounting holes in the pegs). I went to the HW store and got 3/8" (or whatever) Stainless Steel bolts, washers and SS vibration lock nuts. With washer and vibration nut on the inside of the clamp I bolted on the bar to the side of the clamps that had the hole in them that's exposed when the original little bar is taken out (duh, like I could have on the other part <G>). It's not gonna fit perfectly so you have to bolt it down good, the washer will even bend on the inside because on mine it was beveled originally. Make sure every thing lines up and is straight before those final twists of the wrench.
Then I just bolted on the clamps to the engine guard with original hardware and mount the pegs on the ends of the bars. It should look like the above. Here's a GOTCHA. Look at the picture above. See all that room that appears between the new bar and the front fender? Doooooon't youuuuuuu belieeeeeeve it. In the position as the picture show, straight out, it was dinging the fender at the very bottom tip/edge when the forks compressed during riding. I was going to put mud flaps and a small piece of rubber or something down there to protect/cover up the dings. Too late... I sold the bike and got a 1500A.
I was running into the same problem when it comes to highway pegs on the 1500A. I have a F&S engine guard on it and as you can see from the picture above it's shaped in a manner that there's no vertical or horizontal place to put on regular clamp-on pegs so that they're parallel to the ground. Options include A) fashioning a bar similar to what I did with my 750 B) purchasing $200 pegs made to fit in that type of setting from a manufacturer C) getting $15 foot pads that clamp on to the engine guard (I like these except it would put my right foot waaaay too close to my DG exhaust pipe. D) something else.
So I did something else. Was too easy. I was thinking that all I needed to do was get the peg to sit at an angle in on the provided bracket. Well they "say" they're made to do that, but no amount of tightening will keep the peg at an angle to the clamp post once you put your foot on it, I tried. So I'm thinking that I just need a metal wedge of some sort. I was working on some mounting brackets for my trunk (wanted to do away with the Velcro) and had a little 1/8" bar stock left over and I cut a couple of shims out of it (good ol' Dremel). I had already temporarily mounted the pegs on the bike to find out what angle I needed them to be at to be straight so I take two of these shims and they slide snugly right into place on top. 1/4" (the two shims) was absolutely perfect to create the proper angle. So I took a rubber band from some asparagus <G> (those real wide ones) cut off a couple of pieces and used them between the clamp and engine guard for a better grip and clamped on the pegs. They are mounted just as the tube becomes round again after bending downwards on each side. This means the clamps are pointed downwards at an angle and the pegs are angled from that to be parallel to the ground and top crossbar of the engine guard. These are the same ones (I kept them "just in case") from my 750.
Now I did not mount them completely perpendicular to the bike. I put them angled towards me a little so my foot rests on it straight instead of having to angle my ankle. My legs are long enough to rest on them comfortable, none of this might work for someone else.
Where did you want to be today?