Eric,
careful grinding away of the surplus alloy casting from your existing inner chaincase followed by some really neatly finished alloy welding is also an option.
But for outright replacement, the chaincase you need is from an Indian home market kickstart 350 Electra from about 2003 onwards, when the factory swapped from CDI to TCI ignition.
The kickstart versions were made in two versions, one for the right foot shift model with the 4 speed gearbox, and one very rare type for the 5 speed left foot shift gearbox (think hens' teeth or rocking horse manure). If your Electra-X has already been converted to right foot shift that will make things a little easier as the cases are in SLIGHTLY better supply (I actually bought my last one from Hitchcocks', it was one of their unlisted stock).
If you can only get the 4 speed inner case, you can probably get a decent machine shop to put a hole for the gear change shaft in the right place, using your E/S inner case as a guide.
Part nos. 502028/A for the 4 speed, 502029/A for the five speed with the hole for the gear shifter.
This is the right foot shift inner case.
However, if this is going on an E/S crankcase half you will have to drill and tap three holes to mount it, as the countersunk M8 screws which hold the Electra-X inner electric start chaincase in position are in a different position to the kickstart chaincase's fixing studs.
So here's what has to be done:
E/S crankcase half
K/S inner primary cover, the chain tensioner stud hole lines up but the mounting holes don't.
Line the chaincase up on the chain tensioner stud, use a 10mm drill to mark the new hole centres.
Drill out for new M8 studs, 6.8mm is the tapping size.
8mm tap time.
All being well everything lines up OK.
If you're careful you can do this with the engine still in the frame, I have done this twice.
Finshed result on my old Electra-X
I hope this helps.
A.