Nice to hear someone else's thoughts on SEBO and the choice to go with them. Similar with me - parents had a Hoover Junior for many years, then bought the Vax Powa washer tub but then felt a couple of years later that it was getting too heavy for them - hence my collecting starting point with the Junior U1104 and Vax Powa! Then they got an Oreck XL which was ok but my mum couldn't stand the noise and my dad was fed up changing belts on it. My uncle then landed a job in Canada as well as meeting his future wife and they emigrated, leaving behind their SEBO X1 Automatic. That's how it came to us and for 13/14 years it still remains in the family - it has only ever required one drive belt replacement. We eventually bought an X4 and the old X1.
I bought the tool kit way back in 2000 at some point - it used to be on sale at John Lewis for about £40 which was far cheaper than the silly prices online. JL no longer stock the tool kit which is a major pain although I think they can get it in by special order. To be honest, my parents never used the tool kit much except for the dust brush and the extension hose and eventually when I got the complete set, the straight tube was immediately used with the Felix.
Last year when I saw the differences of colour I tried to order a dark dusting brush from John Lewis but was told that this is an "old part" that is no longer on sale and they were only using the photo for sale purposes. Upon contacting SEBO, they have never heard of the dark grey brush, so it was a bit disappointing there. I guess if you have a Felix, that should be sufficient for colour coding the machine up - I'm not that fussy when it comes to coordinating colours etc with the SEBO X uprights. I hope SEBO are still selling the X1.1 as that's a good starter model - and its really no different to the X4 save for a slightly higher motor. Both X1.1, X4 and X5 can use the stair turbo brush whereas some of the X1 Autos can't use them, as they sense a block in the hose and turn off. 'Away to look at the brochure - thanks for that info!
Check by Euronics - they have an exclusive SEBO X4 Pro (for several months now) similar colour to the silver and black Pet though I think it may be dark grey and silver. They also have a K1 Pro which is based on the K1 Pets but in grey. Not to be outdone, John Lewis also have their exclusive model, the X4 Excel.