You're right that the cartridges are standard 5cc EFD syringes. If you'd like to test your own materials, you'd just need to fill one of these to a max fill level of 2mL (we centrifuge our cartridges to remove air bubbles as well).
It's very likely that you will have to adjust the advanced print settings to get good dispensing quality with alternative materials, since the current settings are tuned specifically for the conductive ink. These are accessible through the gear icon in the top right corner of the screen, and can be adjusted in between prints - meaning you can click 'STOP' when printing, adjust the parameters, and click 'PRINT' to pick up where you left off. If there is enough interest, we can publish a user guide on adjusting these settings and explaining how they may affect your print.
We haven't tried dispensing any SMT adhesives ourselves, though we have tried a number of conductive epoxies which should be in a similar viscosity range. Adhesive could be useful if you have an SMT component that will be under a fair amount of stress or if you are worried about tombstoning.
What I would do is use the Solder Paste workflow to 'trick' the printer into dispensing your adhesive, like so:
1) Modify your circuit design so that there are 'pads' in the shape and location of the adhesive that you want to dispense.
2) Export your gerbers, and make sure that the .GTP file includes these 'pads'.
3) Enter the Solder Paste workflow, and proceed as usual until you get to the PRINT step.
4) Ensure the print settings are adjusted for your new material, and select the 'pads' that you wish to dispense on.
5) The V-One will dispense your adhesive material in the selected areas.
If you happen to try experimenting with etch resist or Chipbonder, keep us posted on how it goes! I'm very interested to see what you come up with.