Some considerations before you move forward:
Cost - Cost is the highest design priority, especially in consumer electronics. For large production quantities the NRE will be amortized quickly resulting in a lower product cost. Replacing discrete components significantly reduces test time, PCB rejects and their associated expenses.
Size - The market demands size reduction, particularly for portable and hand-held devices; and requires ever higher levels of integration.
Performance - Matching and tracking characteristics of IC components, digital self adjustment and other techniques can eliminate manual adjustment of circuits.
Power Consumption - An integrated design consumes less power due to lower capacitive loads inside a chip.
Reliability - A single IC is more reliable than a PCB populated with discrete components or multiple IC's.
Intellectual Property Protection - Simple hardware copying is prevented because of the exclusivity of the custom IC.