ive thought about the tail gate idea a bit, iam leaning more towards putting a large chopping board on a slidder set up so i can keep dirty bait juice of tail gate and easily wash it down. similar to a fridge slide

 I have also been thinking of something for the tailgate cutting board mostly but I like slide idea thanks gillyL

 I just use a small fold out table from bunnings, the white plastic topped ones.  That way it can be closer to the water , washed down after and no juices running into the tail gate.

Little trick to stop waves knocking the table over if swells up is to put a short rod holder in sand and put one leg of table in it. 

White plastic camping tables are the go.....
I use an old card table when beach fishing.
Had it for the last 25 years still works for me.
Set it up where I want; put the bait in an old oven dish (to control the juices), tackle box and coffee, couple beach chairs next to it, when finished; wipe it down...
Some people use rejigged ironing boards for filleting...
I suppose if you want to drive around in a car that smells like rotten bait as the juices seep into every nook and cranny then have a crack at it???

i quiet often have my bait board sitting on the tailgate. i hate seeing the juice run all over the joint and unless uve got a supply of fresh water the only thing nearby to wash it down with is salt water...my mates got a roll up ally table that he uses, the table top is made from rectangular tubes and the legs fold up much the same as those chairs that fit in a bag

not bad 

check out my Facebook page "AMH Plastic fabrications" I have made quite a few bait boards that locate over the trays of utes and are fully sealed so no juice can get back into the tray.
cheers