No, It won't

The dh tubes will still pinch flat easily, or would have to run super hard tyre pressures. 

Although the single ply rear tyre with an xc tube i'm running , hasn't punctured yet.

Hmm, im tempted to give it a go the single ply highrollers are cheap and i have some maxxis dh tubes in the cupboard...

Its S**T burt, i got loads and loads of puncture when i ran single ply's with DH tubes on my Balfa. Got 3 in one day in the space of about 2 hours!

I ran 2.5 single ply high rollers and It was only ever the front one that pinch flatted.

a dh tube won't help much, Probably make it weigh almost the same.  

Surely , Your making a BIG compromise, Just to save a bit of weight.

How about the tramps tubeless?

Get a 20" BMX tube.  Stretch around your rim.  Cut around the outside of the tube then open up, this now acts like a Stan's (Stan's No Tube) rim strip but wider.  Insert you single ply tyre.  Add a cup of latex, then pump up hard using techniques shown on Stan's website to spread latex.

There you go.  Single Ply tyre.  No flats.  Little Money (i got 1L of latex from my local art shop for £10).

Admittedly it sometimes won't work.  It's messy.  You can't easily change tyres.  You need BMX tyres with some kind of lock ring on the valve otherwise they push through when you try and pump them up.  I met a whole load of bikers in Oz though who swore by it.

Let me know what you think.