No, there is no way for a sorcerer to craft items that require spells he doesn’t know. It is one of the main reasons why sorcerers rarely bother with crafting; learning spells just to craft things becomes exceedingly punitive. (My first-ever character was a sorcerer that I initially imagined would craft things; I quickly abandoned the notion.)
The warlock’s imbue item ability gained at 12th level is an extremely powerful, and rare, class feature. Because it’s stapled to a warlock, a relatively weak class, and because it comes at 12th, which is quite late in the game, and because he needs to take Item-Creation feats himself (or, better, take two levels in the chameleon prestige class, but that delays things until 14th level), the warlock is fairly limited in what he can do with imbue item, and it’s rare for a warlock to cause problems.
The only other class that gains a similar class feature is the artificer, who gains the item creation ability at 1st, and then proceeds to get a whole feast of Item-Creation bonus feats. This ability alone is enough to make the artificer one of the top-5 most powerful classes in the game, and a well-played artificer (which, admittedly, is extremely difficult) is very capable of breaking the game. (Mind-bogglingly, you can actually ignore this feature entirely and still play an artificer who is ridiculously overpowered—the class has an awful lot going for it.)
Now, the sorcerer, as a class, is also extremely powerful. Not as powerful as an artificer—but probably more powerful than an artificer who doesn’t use his item creation, which means, effectively, that a sorcerer with item creation would be even more powerful than an artificer. This is something you should keep a very, very close eye on as DM.
The other issue is that the crafting rules... kind of suck. As I mentioned, playing an artificer well is very difficult—it tends to need extensive spreadsheets and planning, tracking all the various resources you need and figuring out optimal items to build and when to do so. In many ways, would-be crafters fail to live up to their immense potential because it takes an awful lot of player-work to use. If crafting is just a side-hobby for this sorcerer, it might never be a problem—or the player may not end up bothering to craft that much, because it’s tedious. So it might be safe to allow, but again, keep an eye on it. If the sorcerer goes all-in on crafting, reducing the costs and increasing his efficiency, the power-level of the sorcerer himself and the party as a whole can sky-rocket quickly. This can be difficult to handle as a DM, so you will want to see it coming and have ideas for what to do if it does.
