Cold fermentation with warm maturation is how the majority of German lagers at breweries of varying sizes are now made.
Well, warm compared to the -1 or -2Â°C they were maturing at before. I haven't heard of any even vaguely traditional german larger breweries that are taking their lagers up to the high teens.
But, i have heard of a lot of industrial lager breweries of the type generally frowned upon by lovers of home and craft brew who do exactly the process being described (taken to its logical extreme) - start cold, warm right up, basically skip maturation because its fundamentally over in primary - just really doing it to precipitate and drop solids. I happen to work in one of them.
Its not that pushing a fermentation along towards the end is a bad thing - i do it myself and tend to get lagers from brewday to tap in under a month. But it can
be a bad thing. Speed up the process, cheaper faster, very nearly as good - speed it up again, cheaper faster and again very nearly as good, but only as the previous shortcut, not the original - and you can just keep going till you can punch out a lager in the same time you can punch out an ale (and you can speed your ales up in the same way too)
There is nothing wrong with this sort of stuff per se - but it is a quality compromise, one that you need to be aware of and monitor if you plan to keep making the sorts of beers that homebrewers talk about wanting - go too far, lose your self critisism in the excitement of fast easy lagers, and you'll start to turn out mega lager clones instead. And its a lot faster and easier to buy a case of Coors than it is to brew your own version.