A more expensive but more elegant solution which is likely known by many laptop owners:
The insert is a perfect fit after you remove the unneeded front bezel. The model linked above accommodates 2.5" laptop drives up to 12.7mm tall.
I thank a helpful member of the forums at 123macmini.com for this tip. I'm not affiliated w/ the vendor but am happily using their product.
Quote from Brian Mandell:
Anyone else try this recently?
Thinking of giving it a shot on my late 2009 2.53.
I'm awaiting the slim- to regular-SATA cables (from Amazon) to do my late '09 2.53. Have a WD 640GD installed and am replacing the optical drive w/ an OCZ SSD. Follow a print version of the instructions while doing it and you'll be fine.
Quote from Miroslav Djuric:
We have approached some vendors in regard to a custom cable. However, the prices that vendors are asking makes the cables quite unattractive to buyers. The only way to offset this equation is to get a bunch more requests for the cables. This would enable us to order a much higher quantity and pass the savings on to the buyer.
This guide is great -- but now a bit old by internet standards. Is there still no 15 pin standard SATA to 6-pin slim SATA adapter available today? If someone has spied one, product # and/or links to vendors would be super!