Yes, and I am talking about proper custom designed cheques, printed by an approved printer and with a design approved by a bank.
The revenue stamp cannot be included in the printing without a licence from the Revenue and, if it is included in the printing, the design of the stamp has to be the Revenue-approved design, and not a variation of your own or of the printer's.
There's nothing to stop you printing up an
unstamped cheque form, as fancy as you like, as long as it doesn't include anything that looks misleadingly like a revenue stamp, and then dealing separately with stamping when the cheque is actually written (though, as discussed above, it'll be a pain).
Incidentally, the word "Ireland" that appears under the medallion stamp is not part of the stamp itself. Its inclusion is required by a specification of Irish Payment Services Organisation Limited, the company which runs the cheque clearing system. A cheque that doesn't comply with IPSO specifications can still be valid cheque, but the automated clearing system will or may be unable to process it, and it will have to be specially cleared, a service for which banks normally make a charge.