Would anyone be able to tell me the size of the oil drain plug from a 1999 Suzuki DR200SE. I lost mine while riding and I am trying to find something to use to plug it with until my new one arrives. I really just want to check and see if the bike is going to turn over again.

I am not 100% sure but I had my wife's 1997 Djebel 200 in bits yesterday. (Clutch sticking badly from corroded steel discs , the poor bike lived on a wine farm before we recently rescued it :-)
It's a 14mm thread and afaik all 14mm Suzuki bike sump plugs are M14x1.25.
You can get a short M14x1.25 bolt from the next fastener shop. Get it cut to size (some 12mm thread length) on a lathe or if you are desperate DIY with a hacksaw. Make sure the thread is rolled all the way to the head so that the plug goes in all the way and seals (with a new aluminium crush washer, replace every time you change oil, costs only little but keeps the sump plug where it belongs).
You can also try automotive dealers or bike shops. Many sell aftermarket sump plugs with little magnets which are supposed to fish for broken intestines of your engine.
Just be careful not to end up with a M14x1.5 plug which is used for Yamahas and cars. It will go into the thread a little bit and if you force it further you'll mess up the sump plug thread in the engine.

A little favour in return: What is the manufacturers model code in your bikes VIN? I am trying to source an original workshop manual for the Djebel 200(SH42A) until now without any success as I could not find out where the Djebel was officially sold (not here in South Africa). Might havebeen a Japan only model = only japanese manuals, shock!
Knowing that the DR200SE is near identical to our Djebel (except headlight, speedo and luggage carrier) I might get the manual for the SE as it should be easily available (200SE sold in US, some EU countries and even in South Africa). But I will need the model code, please!

Thanks for the reply what part of the VIN would that be in?

Your VIN should look similar to this of a DR 650 SE:

JS1 SP46A 000 507316

JS1 afaik. stands for a Suzuki motorcycle

SP46A is the model code (here DR 650 SE) That's the part I need off your bike.

The three zeros are gap fillers but can be used to differ between models / variants.
The last six digits 507316 give away the year model and actual serial number.
Some older bikes and some bikes for specific markets might not have the JS1 and the three zeros but I think this 17 digit VIN system was introduced as a worldwide standard sometime around 1990.
Hope yur DR200 is well