da gino wrote:1) Does the plumbing from the drip tray have to go straight down or could it wind to the back - ie would I have to drill a hole in the top of the cart? The same question goes for the line in. (I'll probably build a cart and in case I used it for something else later I'd rather not have a hole in it, but most of all I want the plumbing to be inconspicuous).
Line in is easiest because it is under pressure, so it can run any way you want it to, as inconspicuously as possible. Drain is harder, because it needs gravity to help it drain; on my lever machine, the line is anything but inconspicuous, and because it dangles in the drain bucket I use, it sometimes doesn't have enough head of water to push its way out, so it backs up unless I lift it out of the water. I plan to remedy that sometime. Sadly, it works "well enough" for now, so doesn't get the attention it needs.
da gino wrote:2) how thick are the usual lines for plumbing in and out? Are there sleeves or something that they both could run through that dress them up/ make them look less obvious or is that also a bad idea?
Line in can be 1/4" tubing, which is what I use. Drain is tougher - the bigger, the better. There are specific guidelines on sizing and slope of drain lines.
da gino wrote:3) I am always nervous about water bursting for lines running to dishwashers/washing machines/ ice machines. On the other hand getting water to the machine if I do not use a flojet will require running some form of pipe between the main floor and the basement ceiling (not a drop ceiling, but I don't mind a little patching). Is there a high quality pipe that you don't have to worry about ever bursting, but is easy to run through finished space? (the joist run the right way - ie parallel to the direction we want the water to run) if that is any help).
With the flojet, you can just turn it off with the espresso machine when you're not using it.
plastic tubing isn't likely to be a problem - you're more likely to have problems at the fittings than along the tubing.
da gino wrote:4) If I did run it with a flojet out of a bottle I'd probably build a cabinet in the cart to hide the bottle. How much height does a flojet add above the height of the bottle?
It does add a little bit of height.
Here is what I have set up in the cart in my office:

As you can see, the flojet adds some height to the bottle; there is also a large diameter tube that goes between the control unit and the siphon unit, but then 1/4" tubing from there to the machine.
I fill the bottle with filtered water about every 2 weeks; when it's time to fill, I first dump any dregs, then put a gallon or so of water and a glug of bleach in the bottle, shake it up, let it sit 5 minutes on each side, then empty it. That keeps any funk from building up in the bottle.
The drain bucket gets dumped after every session (daily).
On my home machine, I feed it from a plumbed in line, and drain it into a bucket. 1/4" tubing is easy to run anywhere - drain lines, not so much.