This may be a bit extreme, but perhaps you could take a much more common beige Mac Plus, chop it's handle off in approximately the same place, and somehow JB-Weld/chemically bond that into the void left in the 512K ED.
It's a lot of work, and may not look absolutely original, but it's worth a try.
Alternatively, you could leave it as is and install a big fan in there. These machines need all the help with cooling they can get.
Congratulations on your find, though!
Main Macs: Early 2008 Mac Pro, Mid 2009 MacBook Pro 15", Dual 1.25GHz Power Mac G4 Mirrored Drive Doors
Secondary Macs: Dual 2GHz PowerMac G5, 1.67GHz A1106 PowerBook G4, Core2Duo-Upgraded Late 2006 MacMini
Wanted: G4 Cube, Lisa, TAM, PB Kanga