I made an account just now to share with you haha. But I just found the forum, and figured I will be sticking around for a while. Forewarning, this is going be a little long winded... I am currently building a cb650 , and swapping out the stock seat is high on my agenda. But like you I'm faced with the predicament of wanting the best of both worlds. So far, this is what I have come up with after a lot of brainstorming and trying different designs on my cad software (bear in mind I'm just in mock up stages). The plan is a boat tail, like the one on the bike that I have attached. This is the bike that inspired the shape and style as well as confirmed that it will look nice. I plan on having 2 rails attached to the finished project right below where I will mount the tail light running along the inside of the peice, that will be used to slide into the frame rails that run below the seat itself. Of course, you will have to chop the frame a bit and make adjustments. I will be leaving an opening about an inch or two near the bottom of where the back rest will be (the only opening left on the cardboard mock up is where the back rest will be) so that a smaller flat seat (similar to the one attached, another project I am brainstorming ha) can slide in. I haven't decided how I am going to tighten the rails down so it isn't sliding around once assembled, but you get the idea and potential of the adjustable boat tail at that point. The idea is to have a simple set up, so I can loosen/adjust/tighten it on the fly. The boat tail is also going be set up to hold my battery attached to the top... I think. I'm going to using fiberglass, If not than stainless with tig welds. I'm not sure how much work you were wanting to put in this, but In my head it's a pretty straight forward, and it seems like a fun project to figure out as well as a potential to learn some fiberglass. Look into it if you're interested. Everything I've thought of doing has been done, and found really easy with Google.