The details of this lightsaber were based on some drawings, the Star Wars Technical Journal, and an Icons Darth Vader lightsaber that I own. There appear to be some discrepancies in the different photos, so I've got 2 different drawings for you. As it turns out, the saber is not based on a Heiland flash handle. It is based on a MPP (Micro Precision Products) MicroFlash. As for current day availabilty of the MPP - They do exist, they just go for quite a lot of money on ebay.
A larger version is available by clicking on the above image.
A larger version is available by clicking on the above image.
This saber was created from a Graflex 3-Cell flash. Apparently when it came time to shoot, they couldn't find a Vader saber due to loss or theft, so they took a Luke ESB saber and rebuilt it. The took everything off including the clamp which was replaced with a black (likely hard rubber) one similar to the above version. The lower part of the black emitter shroud was created from scratch, and from current photos, looks like it was machined and painted and the protruding lip of the Graflex handle was also painted black.. Six holes were punched for effect I suppose, for design only reasons and filled with what look like allen wrench screw tops. Where the clear button (or second red button) was originally located, a silver piece was added. Finally they used 7 instead of the usual stand 6 grip pieces and left the original (well as in original Luke ESB) belt hook clip in place and added a second smaller one near the location of the ANH\ESB one's for consistency.
A larger version is available by clicking on the above image.