I've decided to post Captain Jack's question below both here on the Net's "Western Florida" section and on the "Ask Your Neighbor" page, in hopes that we can get a response. Many thanks in advance!
For those not familiar with Matlacha Pass, it lies east of Pine Island and Pine Island Sound. Navigation of its southerly section can be VERY tricky indeed!

Subject: Matlacha Power Lines
Cruising News: I have got two different power line heights for the south side of the Matlacha Bridge on Pine Island. One says 75 ft. ( A Guide to Anchorages in Southwest Florida) and the other 45 ft. (Navionics Nautical Chart).  Does anyone have 1st hand knowledge?? Tried Lee County Electric Cooperative (239) 995-2121 Engineering department said their policy is "Not to give out that information", what's that all about??
Jack

Subject: Matlacha Pass Power Line Height
Cruising News: The only information I've seen is that on the West Coast of Florida Chartkit which shows 47 ft at the channel – and, from motoring under it, I'd say it looks pretty accurate, though I'd hate to test it with a mast
Mike Smith