Old and busted 12J in my garage. Any fun frankenstein options?

[BopEuph]

The first (bad) tuba purchase I made was over a decade ago for a beat-up 12J. I thought it could be repaired, but it's just sat in the garage forever in pieces. The best part is that it came with the hard case, but I hate tuba hard cases, since they take up so much space.

From my memory, since it's been years since I opened the case:

The bugle is in good shape.

The bell is trashed.

The valve cluster is in okay shape, but the lead pipe was ripped off. I've been told a brazing would be possible, and a friend (who's a good repairman) is willing to braze it back on, but we're not sure it will work well.

Is there a fun tuba project I could create with this, from anyone's experience, without doing the lamp or urinal conversion? Maybe with a few more parts, we could build a new horn?

[LargeTuba]

The 12j is a fun little tuba if you just want to get it to working condition.

You can always add a valve or two. If I can do it, you probably can too.

[BopEuph]

My gigging horn has been a great playing 12J for a long time. When I got the playing one, the bugle was so dented I thought I'd use the one from the busted horn. But the dents were pulled so well that my working 12J is in incredible condition and sounds great for pit, jazz, and strolling gigs (though a bit too quiet for the latter).

I'd love to do something with it that's not trying to be another 12J, though. Maybe ANOTHER donor 12J and try to make essentially a 5J, or get some more parts and try to make a homemade python tuba, or a cimbasso, or something like that.

[Tubajug]

I've got a 12J carcass I've considered cutting to CC just for fun. It would essentially be a homemade 2/3J.

[BopEuph]

A buddy has a donor YBB321, and I think between the two horns, I could probably come up with a Python tuba in BBb.

Though the valve block would need serious reworking trying to make it more vertical, and the broken leadpipe on the 12J might introduce issues...maybe I could use the valves from the 321 and craft a kind of 4V front action with a very vertical block, but something tells me it wouldn't work with what I have...

Though I'm totally unknowledgeable about this, and this is probably an over-my-head idea, complete with no workbench or tools at the moment.

[BopEuph]

I'd also love the input of @Dan Schultz and @bloke about this likely bad idea.