gistfile1.js

// Add G, [minx, miny, maxx, maxy] as a bbox option to polymaps, after line 212:
        case "G": {
          var nw = po.map.coordinateLocation({row: c.row, column: column, zoom: c.zoom}),
              se = po.map.coordinateLocation({row: c.row + 1, column: column + 1, zoom: c.zoom}),
              pn = Math.ceil(Math.log(c.zoom) / Math.LN2);
          return nw.lon.toFixed(pn)
              + "," + se.lat.toFixed(pn)
              + "," + se.lon.toFixed(pn)
              + "," + nw.lat.toFixed(pn);
        }

// Then add your geojson

map.add(po.geoJson()
    .url("http://localhost:5984/sf_bike_ped_acc/_design/gc-utils/_spatial/_list/geojson/geoms?bbox={G}")

// Should be able to write one function with a number, per zoom level, like geojson_{num} and do a full tms style map in polymaps:

map.add(po.geoJson()
    .url("http://localhost:5984/sf_bike_ped_acc/_design/gc-utils/_spatial/_list/geojson_{Z}/geoms?bbox={G}")