Not Your Regular Wetsuit Questions

Electrical tape isn't as stretchy as the wetsuit and the adhesive doesn't hold well in the water, so you'll most likely lose it during the swim. 

If you've got the typical zipper down the middle of your back, why not replace the normal black pull strap with a high-vis pink or green nylon web?  (This might even be visible while you're in the water). 

You might also use some spray paint (maybe test this on an old piece of scrap neoprene or a neoprene cap so if it does eat the neoprene, you haven't ruined the rather expensive wetsuit).  Use a bright color and spray the shoulders and possibly the arms.  Yea, the paint may flake off some, but should still be mostly there the whole swim.  You could also spray-paint the swim cap (stripe down the middle?) 

Wear a different color swim cap than your wave.  You may need to check with the RD but some races use all the same color, some have different colors for different waves.  If the race uses all the same color it should not be a problem to wear your own so you are more visible.  It may not work in all races but a good solution when possible.