Excite Truck was by far my most played launch game. Love Bots too.
Did Monster also make World Rally? Loved that one too.
Yup, they did. Since they've been working with Nintendo they've made:
Excite Truck (late 2006)
Excite Bots: Trick Racing (early 2009)
Excitebike: World Rally (late 2009)
Pilotwings Resort (early 2011)
Donkey Kong Country Returns 3D (summer? 2013)
The team is quite small (and recently lost its lead programmer/co-founder
), which could mean that DKCR3D is their next project and nothing else is in the works. DKCR has a lot of assets to start with, and if there are going to be added features to the game, that could explain why it has taken them this long to port it. Pilotwings Resort may have had unique contents, but it was not nearly the same scope as Donkey Kong.
On that note, I would not be surprised if they were working on something else before Nintendo had them drop/pause it in favor of getting DKCR onto 3DS this summer. Perhaps PWR was going to get a sequel or another Resort-based spin-off but was cancelled due to lagging 3DS sales? Hard to say.
I think Excite Bots was their biggest bomb of the lot, which is a shame as that was probably their most expensive/intense project. The fact that the team has been using more first-party-assets in their games tells me Nintendo is using Monster Games as a more budget developer at the moment, so a huge project like F-Zero 3DS or DKR is probably not going to happen until Monster earns Nintendo some big bucks.
If they have anything else in development right now, it is either a DD title or coming 2014.