Three letters...
L.E.D. - They are cheap (2 bulbs at home depot for $4)
They run very cool, and cost almost nothing to run.
I bought this 12 volt LED bulb off ebay for 10 bucks. It has 37 super bright white lamps inside.

12 volts means the snake can never get shocked, LED no burns.
Another option is, go to a junkyard and pick up 2 matching dome lights from a car or SUV, install LED bulbs, cut out ports with a jig saw, and install the dome lights. Done with care would make a very nice unique box.
Adapter transformers are cheap at radio shack, a small 12 volt pack like one for an answering machine works fine.
Good luck,
Wayne A. Harvey
-----
1.2.9 Storeria dekayi Casper, Xena, Athena, & Kids
0.0.2 Thamnophis marcianus - Checkered Garter Snakes
0.0.1 Thamnophis sirtalis - common Garter - Princess
0.0.1 Nerodia sipedon - Water Snake - "Aqua"
0.1.10 Storeria occipitomaculata - Red Belly snakes
0.0.1 Amelanistic Corn Snake "CY" Juvinile CB
0.1.0. Pueblan Milk snake "Oreo" adult CB
1.0.0. ASIAN GREEN SNAKE 3' WC Cyclophiops major
0.0.1. Savannah Monitor "CHOMPER" CB
0.1.0. Green Anole "Crystal" WC
1.0.0. K9 "ACE" Black Cockapoo
1.2.0. Feline"Felix" "Kaja" & "Silver"
0.1.0. calico RAT
2.4.?? Mice - Feeder farm - Crickets / fish
More herps than I could ever list out back on the land. 