I claim the ornamental design for a suitcase with child seat, as shown and described.
FIG. 1 is a perspective view of a suitcase with child seat, showing my new design.
FIG. 2 is top view thereof.
FIG. 3 is a bottom view thereof.
FIG. 4 is a front elcvational view thereof.
FIG. 5 is a rear elevational view thereof.
FIG. 6 is a left end elevational view thereof.
FIG. 7 is a right end elevational view thereof.
FIG. 8 is a perspective view of a suitcase with child seat showing my new design in an environmental use.
FIG. 9 is a perspective view of a suitcase with child seat, showing my new design with a seat back of the design in a down position.
FIG. 10 is a front elevational view of a suitcase with child seat, showing my new design with the seat back in the down position; and,
FIG. 11 is a rear elevational view of a suitcase with child seat, showing my new design with the seat back in the down position.
The broken lines depict portions of the suitcase that form no part of the claimed design. The broken line showing of a child in FIG. 8 is for environmental purposes and forms no part of the claimed design.