At the cost of extra refresh, you could probably rework a Sponsored Magic (Kem Lore probably the best bet) to work for Wards, so you can cast them with Evocation Speeds and Methods. Biggest difference between a Ward and a Block? The whiplash the attacker feels, if they fail to meet the Wards rating.
That, and if you got powerful enough, you could implement Landmines into the Wards at Evocation speed.
Of course, whether or not you could cast a Ward upon the area around you is debatable, even with such a power. But we know the Merlin didn't anchor his to a building, which is the basic premise of Wards. So maybe it is possible to anchor them in other ways, perhaps to a 1 metre-diameter circle of the ground your standing on.
Based on the summoning in Changes, am wondering if anything is actually needed to ward. It might be good enough to just picture everything in your mind strong enough to get away with those pesky requirements. Now the concentration needed would be immense, but at least in the above example, there is a reason why he is The Merlin......