Blue,
Neither the C-27J nor the C-295 can transport armored vehicles such as the LAV III. Land Rovers and HUMMV's are the limit. Even then, they cannot carry them very far - increasing payload reduces range. For instance, C-295 can carry an 8000 kg load about 1200 NM's, while the C-27J is very similar, a 10,000 kg Payload 1000 nm or a 6,000 kg Payload 2300 nm. Basically within Europe.
Pilatus,
There are no more ex-RAF Hercs left on the market. In fact, there are virtually no used Hercs left on the market anywhere, hence the RNLAF having to draw two hulks from the US boneyard for rebuild by Derco/Marshalls - and there are not many more left in the boneyard that can be practically rebuilt. There are former USAF E-models coming available, such as those the US is gifting to Poland. But they are truly used up. The Poles will spend some $18 million each to make them operationally functional, including new wing boxes and a complete avionics upgrade, and even then will likely face serious problems and low availability. Ditto the Austrian former RAF K models. They received only a basic overhaul from Marshalls, hence the need for three just to have one available. The RAF may be willing to sell-off 10 130J's to help fund another C-17, but Canada will probably snap them up as interims while they await delivery of at least 16 new J-30's from about 2011 - the soonest Lockheed can promise new deliveries given their full order book.
Here's another option for Ireland. A-400's from an EU "pool". Expect that as part of the emerging European Airlift Group (EAG), additional A-400's will be ordered by the EU to form a "pool" operated by member states under the EAG. The concept originates from the single A-400 ordered by Luxembourg that was to be operated by Belgium, but is now under consideration as the first EAG "pool" aircraft. The IAC could sign up to operate one or two EU A-400's, with bed down at Baldonnel (or Shannon), on a mix of national and EU taskings. Training and maintenence would be under the auspices of the EAG A-400 program. Other nations interested in operating pool A-400's include Czech Republic, Hungary, Slovakia, Slovenia and the Baltic states. Given expected A-400 deliveries from about 2012, look at an interim solution of C-295's, possibly leased through the EU, to potential pool countries. Impetus for this is really hot now after the tragic Slovak AF AN-24 crash over the weekend that killed 42 troops rotating out of Kosovo. Everyone now realizes that all the old, unsafe and poorly performing transports in Europe have got to go and soon, coupled with the recognized requirement to vastly improve European airlift capabilities across the board.
The point here is to seek out original, practical solutions within the EU framework, since that is the basis of Irish defence policy now. The IAC and the defence ministry should be engaging with the steadily evolving EU military organization to seek every advantage equitable to all parties. Hopefully they are, but sometimes I think the IAC/MOD suffer from a dearth of imagination and a reluctance to dveiate from the comfortable status quo. If they don't, Ireland will not be doing all it can to support EU military acitivites and the IAC will devolve into an airshow flying club.