Paramount Property Development has been issued a $1.2 million building permit to rehab an old warehouse at 2200 Locust into a residential building with commercial on the ground floor. A planned unit total was not available.
Below is a Google Streetview capture of the building:

The Station G Building (4427 Chouteau) on the old gasometer site in Forest Park Southeast may soon see an $800,000 rehab into 11 apartments. A permit was applied for by developer Station G LLC on November 15, 2012. It has not yet been issued.
Below is a photograph of Station G from nextSTL. Click here for an earlier nextSTL story showing that the Station G building was once threatened with demolition.

The building is the last remnant of Laclede Gas’s presence of the site. Click here (Built St. Louis) to see pictures of the old gasometer structure that once loomed above both Station G and Interstate 64/40.
The remaining Station G building will be entirely surrounded by the 101-unit Aventura at Forest Park development, which is progressing quickly. Per this July 2012 St. Louis Post-Dispatch article, Aventura developers sought to control this building as well but could not agree on a price. It is likely that the building would have then been demolished as well.
Click here for more information on the Aventura project, including a potential expansion of its initial footprint.
The 2900 Indiana Condos Development at the corner of Pestalozzi and Indiana in Benton Park is progressing into its third phase.
The third and final phase of this multi-building development will see the rehab of a vacant single family home at 2910 Indiana, which is adjacent to two buildings already rehabbed in prior phases (one former mixed use and one former industrial building).
A $100,000 building permit has been issued for the rehab of 2910 Indiana, shown below via Google Streetview in July 2011:

Below are shots of the already completed buildings, also from Google Streetview. The first phase involved the rehab of the corner mixed use building at 2900 Indiana. It is now entirely residential.

The second phase involved the rehab of an industrial building with two garages, which have been retained. The building is now completed and also fully residential, though it was not yet finished in this July 2011 Google Streetview capture:

The units in the above building were recently finished and are now for sale. Below is a small photograph of the exterior of the building fully rehabbed from a unit’s real estate listing.

More information on this development is available via the St. Louis Real Estate Society’s blog.
The formerly two-family structure at 718 Shenandoah in the Soulard neighborhood has been rehabbed into a single family at a cost of $80,000.
Below is a recent photograph of the structure:

The National Printing and Engraving Co. Building at 4225 Laclede in the Central West End is undergoing a $250,000 conversion into six residential units. Judging by the owner’s LLC name, the building may be marketed as the “National Printing Residence”.
Below is a photograph from Geo St. Louis showing a zoomed out perspective of the building:

And here is a more recent zoomed in shot, as well as a peek inside, that shows work is underway:


The two-family structure at 3624 Hartford in the Tower Grove South neighborhood will undergo an $80,000 rehab into a single family by 3624 Hartford, LLC.
Below is a Google Streetview shot of the heavily altered building (at center):

A $100,000 renovation is headed to 3661 Shenandoah in the Shaw neighborhood. The rehab will convert this two-family structure into a single family.
Below is a recent photograph from Geo St. Louis:

An earlier Geo St. Louis photograph shows the building with its door and lower windows boarded:

The four family structure at 2909-11 Missouri in the Benton Park neighborhood is under a $260,000 rehab (conversion into a two-family) by owner MAC Fund Club, LLC.
Below is a recent picture of the structure:

A $100,000 permit has been issued to rehab the two-family home at 3838 S. Utah Place into a single family home. Garcia Development is the developer.
Below is a recent picture of the structure. A construction dumpster is on site (not pictured).

Completed last year, the $115,000 rehab of 3520 Oregon in Gravois Park by Neighborhood Enterprises Inc. saw the conversion of a two family to a single family.
The 3500 block of Oregon is a peculiar one, closed at one end long ago to smooth out a large grade change present in the southern portion of the block. A staircase now connects the portion of Oregon where it meets Miami to the rest of the block. (See here in Streetview).
Below is a recent shot of 3520 Oregon, relatively freshly rehabbed:

A Geo St. Louis photograph from October 2010 shows the former state of the building:
