As well as a touch screen monitor there's also the possibility of using a Tablet as a secondary touch input device using MIDI over WiFi.
I looked at that in the past but haven't implemented it so only have research notes rather than hands on experience.
Here are some Windows tools from one company that interested me:http://level6productions.com/
You can buy cheap refurbished Dell Windows tablets from here amongst others and I've dealt with them in the past and found them to be good:http://mcscom.co.uk/shop/dell-tablets-a ... ue-11-pro/
Better to go with the Venue 11 7140 and its passive whereas the 713x models have a fan and a bad reputation.
For a bit more the Latitude 5175 gets my vote as it has more ports I think and a newer chipset and features:http://mcscom.co.uk/shop/dell-tablets-a ... -in-1-pcs/
You can also buy keyboards for these cheaply which turn them into laptops thus making them more multipurpose and also extend the battery life.
Venue 7140 (2GHz, 4GB, 128GB, WWAN, W10) + keyboard dock = £221.
Latitude 5175 (2.8GHz, 4GB, 128GB, WWAN, W10 Pro) + keyboard dock = £298.
Deduct £66 if you don't want the keyboard dock.
An ipad might be a better option but don't have experience of those.