Yes, I love to mixed ferment. Generally though, I'm doing it because I'm pitching an esoteric slow fermenting yeast first - Torulaspora, Metschnikowia, - or bacteria, etc. And giving it a solid 24-36 hours to build character before pitching the heavy hitter.
Why the desire to co-pitch? Are you assuming attenuation is going to be a problem? At reasonable starting gravities, it's not problematic.
I use a number of ale yeasts, none of which have had any issues fermenting down to 1.000sg. S-04, US-05, Nottingham, ECY10, etc. Chalk it up to slightly warmer fermentation temperatures (high 70s), high nutrient (backset), agitation in fermenters to reduce early floc., and mashing with little to no residual dextrins/unfermentables (glucoamylase). Nottingham is hands down, one of my favorite whiskey yeasts.
Couple things to keep in mind.
In my experience, high starting gravities are going to make this more challenging, not less, especially if your first pitch yeast is a fast fermenter. By the 24-36h mark, you've already created enough alcohol to create a stressful environment for the new pitch, at that point there may be enough of the Yeast 1 biomass to outcompete Yeast 2. Reduce the timeframe, and you don't yield nearly the same character from Yeast 1.
To emphasize character of Yeast 1 - consider underpitching at 1/2 typical cell counts - this is to emphasize Yeast 1 character and to slow down Yeast 1 somewhat (yes, it's somewhat counterintuitive). Underpitching ale yeasts and fermenting them warmer than recommended temperature is a great way to emphasize ale yeast ester contribution.
Killer Factor Positive and Killer Factor Sensitive yeasts. If Yeast 1 is sensitive, and Yeast 2 produces killer factor - this may be counterproductive. Pitching a sensitive ale yeast, and then a fast fermenting KF+ yeast a few hours later - you might be wasting money.
Careful with the high-phenolic POF+ yeasts - those phenols come through loud and clear, screaming all the way through hearts. Might be your thing if you like a "peaty" phenol character.
Really fast ferments (4 days) is not going to yield tremendous yeast flavor contribution, so it may be moot. Fast ferments are ideal if the end goal is a cleaner spirit with higher yields, but longer ferments really begin to emphasize character - I think this is especially so with the ale yeasts. Let 'er riiiide.
Maturation duration is a killer of unique yeast flavor contribution. The beautiful fruit and florals of ale yeasts do not stand the test of time. You can have an amazing new make, by the 1 year mark it's already lost considerable character, by the 2 year mark, it's almost gone. It becomes a very, very subtle difference. I always wondered why the big distillers said that yeast didn't make a difference. It's not that, it does make a huge difference in new make ... but at 4 years? 8 years? 12 years?
Concur with @adamOVD on the Champagne as Yeast 2 - EC1118 is very commonly used to rescue stuck fermentations, as it can withstand the stress of being pitched into a higher alcohol fermentation. FYI - It's killer factor positive.