OK, I've finally received my Dell Venue 8 Pro 64gb and proceeded with DAW tests. I know there are quite a few people here interested in such ultra-portable solution and this is my report on how such a device works with audio in general and with Cubase 7 in particular.
First, the bad news: the USB 2.0 port (micro USB, requires OTG cable, presumably it's the same with all the 8" W8.1 tablets) doesn't provide sufficient juice to power external drives and audio interfaces (tested with RME Babyface and Focusrite Scarlett.) Yes, there is a solution, but you will lose some "portability" there: you will either have to use powered external drives and interfaces, or you can use a powered USB hub. Since you'd need a hub anyway to hook up an interface and an external drive (you only have ONE USB port), you might as well get a powered one. It's true that this device comes with a microSD slot that can give you an additional 64gb of storage, but I'm not sure these cards are fast enough for audio recording, even the super-duper "X" types. I guess I will have to test that later (I have a 64gb SDXC on order, should get it next week.)
Since I had many licenses I never used, I installed Cubase 7 AI (the free version that comes with Steinberg and Yamaha hardware.) I really didn't want to bother loading the full version (or buying Essential...) and having to cope with the additional hassle of accommodating the dongle. So, that means I couldn't test Cubase's more advanced features. But seriously, you wouldn't be using Vari-Audio or Note-Expression on a tablet. After all, this is a super-portable solution for quickly sketching ideas and recording on the go. I also installed Sonar X3c, because so far it's the only DAW that has been optimized to run on a touch screen, and I just wanted to see how good the experience is.
Cubase loads fine and works fine. Of course this is not an RT app, but a "desktop" application that can hardly take advantage of touch, but you can still pin it on the start screen for quick access. Now FORTUNATELY the V8P (like all 8" Windows tablets so far) doesn't have a super-high resolution (it's 1200x800), which means that albeit tiny, icons and buttons aren't impossible to deal with, unless you have really fat fingers. But even if you do, you can still manage to accurately point, click and drag with the active stylus, which is quite precise and does the job sufficiently well (yes, there are few annoying bugs, especially with the inking, but Dell has promised a software update for next week that will take care of that.) Unfortunately, the stylus is NOT included with the V8P, it's a $35 accessory (rather pricey IMHO, especially considering it's not a top-quality Wacom device.) Don't bother trying with other active stylii, because they won't work (I read that on the V8P forum.) Sure, a capacitive stylus would work (the kind you can buy for $2 on EBay), but it wouldn't provide a better experience than your index finger.
Performance is quite acceptable. Of course I did not try to push this system by exercising ridiculous CPU demands, I just wanted to see how it would perform in a typical on-the-go "hotel room" session, where the system would have to handle maybe a dozen instrument tracks and a couple of audio tracks. And everything went fairly smooth. So, I believe Steinberg should definitely start working on a touch interface (assuming they haven't already done that), because this type of device will definitely become popular.
And here lastly a word on Sonar X3. Man, that was really FUN!!! Despite the tiny screen, pinching to zoom tracks in and out was more than doable and overall the experience was a hundred times better than Cubase's. Because the X3 interface is also scalable, I found no need to use the stylus at all, everything worked pretty well with my fingers alone.
To sum it up, if you want the "ultimate" no-compromise tablet DAW experience, definitely get a Surface Pro 2 or equivalent device with W8.1/64 and 8gb of RAM. Dell also has a Venue 11 Pro with either i3 or i5 CPU, which still costs a couple of hundreds less than a similarly-configured SP2, but consider that the latter comes with a Wacom stylus that's MUCH MUCH better than what Dell gives you. If you only use it as a pointing device, however, there will be virtually no difference. Bay Trail tablets provide a more limited experience, which is still acceptable within the parameters of an on-the-go session and way way better than what an iPad or Android tablet can offer. Particularly, the 8" tablets provide an unmatched level of portability. After the "briefcase studio", now we have officially entered the "coat pocket studio" era.
If you have questions on this setup, feel free to ask.