I need recommendations on portable single patient R.O. systems. to be used in Acute setting (individual patient rooms in the hospital). They need to be able to run for 24 hours continuously (SLED treatment). Also, if possible, I don't want extra carbon tanks. The extra tanks make them not so portable.

AmeriWater MROS is your best bet. Easy to work on, anti scalant feature. I purchased 2 RO's for a hospital acute program. I was nable to get them to install one .50 cu/ft carbon tank and an extra carbon cartridge filter. All this is inside a cabinet and easy to roll. But the RO must be connected to a water source at all times, because the machine goes into an automatic flush every 4 hours ( or what ever you set it to ).

I found the MROSs unstable when rolling. None of the wheels are fixed, so when one drags it takes the 90 lb. nurse, and slams her into the wall or throws her as it tips.
They do function well, and are easy to work on. A company called Mechanical Solutions makes custom carts to hold RO and dialysis machines together. That auto-flush feature is fully programmable, and can be shut off.
The former GE-now MarCor-Millenium seems to operate fairly well. Haven't had enough problems to say how fun it is to work on the tiny thing. (Softener and carbons are seperate from the device.)
I heard that the MarCor Semper Pure is very reliable, but expensive, and heavy.

I piloted the Lauer Aquaboss/Fresenius 2008K@Home combo in 2004. My home hemo prgram now includes 7 Aquaboss ROs in the field. Recently I replaced the aging 2008Hs with Zyzatech F801 ROs that were in use in one of my acute programs with 2008Ks and Aquaboss ROs mounted on Lauer's Aquadock cart.
The dialysis machine and RO can be locked together and moved as one unit. This makes it possible for the acute RN to bring the equipment to the patient if that's easier.
I find the Aquaboss to be reliable and easy to work on. That's my two cents; hope it helps.