You could just attach something like a bungee from the e=brake to the steering wheel whenever you use it, to remind you.
I've seen motorcycles that have a cord from the front end to the handlebars, and I suspect it's to remind them to unlock a front brake or something.

--- On Sat, 7/3/10, Mike "Rocket J Squirrel" <camping.elliott@GMAIL.COM> wrote:

From: Mike "Rocket J Squirrel" <camping.elliott@GMAIL.COM>
Subject: That's it, I've had it. (Driving with brake on)
To: vanagon@GERRY.VANAGON.COM
Date: Saturday, July 3, 2010, 12:31 PM

This is the third time I've forgotten to take off the parking brake
before driving. It's not like the brakes are so monstrous that I'll
notice on the first quarter-mile downhill away from the house, and my
sitting position places the steering wheel right between the dash Brake
light and my eyesballs.

I'm gonna rig some alarm to sound when the Brake warning light is on and
the transmission is in gear.

Mellow Yellow has an automatic transmission, and the starter won't turn
if the van is not in Park, so there's some wire that connects to a
switch on the shift linkage or something. I can't find that wire in
Bentleys.

--
Rocky J Squirrel
84 Westfalia: Mellow Yellow ("The Electrical Banana")
74 Westrailia: (Ladybug Trailer company, San Juan Capistrano, Calif.)
Bend, OR
KG6RCR