For the 47 onward trucks I think the parklight conversion works well.
I'm a big fan of converting your headlights to the brighter modern non-sealed h-4 style (bulb). I may even go the next step and upgrade to HID/XENON, which just requires the addition of some electronics in the headlight wiring and runs about $150-$200 for the kit on e-bay.
Lots of the vendors carry the headlight lens and bulb kit to convert from sealed beam to replacable bulb, I've even seen them at various FLAPS, like autozone/checker...
I have gotten sets for several cars on E-bay for less than FLAPS/Vendor prices and they have all come with an extra bulb in them for the turn signal.
Here's an example:
http://cgi.ebay.com/ebaymotors/HID-...QQitemZ8050068709QQrdZ1QQsspagenameZWDVW