Get a mobility scooter motor off trade me,theyre 12/24v and work mint,then look at getting a good quality drum/spool made up out of stainless or alloy (10mm) cause a hell of a lot of tension on the drum will encourage fail points,believe me,lol.

My system is a bit crude looking,but it definately does the job,the most weight ive pulled in was a 9kg snapper and a 6ft bronzy on the same set,if anythings going to fail,it will be the joins/knots/crimps in the line,or as i found out a few weeks back,the bridle where the lower kite attaches to the main line.

It can be done fairly cheaply,i make my own dropper lines with stoppers every 2mtrs,that saves me $70,i also make my own trace clips.

the hardest bit of making the setup is making sure your drum can handle all the weight of the line,sinkers,kite/wind and the fish.

Fix your drum onto the axle of the scooter motor with a grub screw so you can freespool it out,then tighten and retrieve your gear.I also have made my winch so that i cal take the drum off the motor incase of an over run or tangle,its no fun unknotting a km or two of line on the beach,with alot of wind,makes it more likely you will lose some part of the line,or have the dropper rig get washed about in the surf,not a nice thing to have to do.

Ill take a pic of my rough and ready winch for you and point out whats what.

But yeah,forget anything thats petrol powered,you only want a meter every 2 seconds coming back onto the drum,any faster and if you get a snag,by the time you notice its too late,your line will snap.seeyaa gear.

I dont use a trolly,i made a offset tripod that i stick into the sand,then tie it to my towball on the truck,for when the wind picks up,or you get a massive strike,cause you can actually feel if theres a big fish on the line,even if its out 2kms,and Ive seen a guy lose the whole lot cause he wasnt watching the gear,wind picked up and pulled it all out to ozzy,lol.

On the right you can see the pole that has a hanger bearing welded to it that acts as an outer breace to stop twisting,it sits through a tubular part of the upright,thats to be able to remove the spool.

On the left of the spool you can see the grub screw/bolt to lock it down and pull it in.

Theres a switch on the back that you have to push and hold to retrieve,as a safety cause if its a simple on/off switch,nasty things happen if your hand ends up in the line,ive had it happen while helping a novice fisher with his gear,never again,i almost lost a finger,its surprizing how fast you can snap 65kg line when you know whats about to happen,he had an on/off switch that i couldnt find on his winch,so i snapped the line.

I hook it up to a battery,or my truck when i pull it in.

Im making a new drum soon out of a ride on mower rear wheel,just the right diameter and width to hold 2-3km.You want the sides to be around 300mm in diameter,and the central axle doesnt really matter,as long as the whole thing holds the amount of line you perfer to use.The thickness of the sidewalls of the drum is very important,as you can see,mine has warped from the tension of the line going onto it.Thats 2mm galv steel with 2, 3mm high carbon saw blades welded on the outside after the galv steel started to buckle badly,and even that has started to buckle again,hence the new drum im making.

Make your trace rack 550mm long,snell on your hook,put the hook in the trace holder,cut your line 100mm after the other end of the trace holder,put the line through your clip,put the clip on the other end on the trace rack and clinch knot the trace,i usually slide the clip towards the hook a litle to allow for the knot to slip tight,thats pretty much it.

Have a look on pauls kite fishing site,its got instructions that are no doubt more understandable han mine.